Warlocks are not Clerics. They don't draw their power directly from another entity. It's typically more of a learning thing; the Patron unlocks the power within the Warlock.
That's mostly up to how you role-play and DMs can alter the rules however they see fit or you can implement house rules at a D&D table but otherwise no, that is wrong. Warlocks are not required to have any magical aptitude and they are not wizards who learn their magic either...no, warlock powers are granted by their patrons. As a rule: wizards learn magic, hence intelligence and all the faffing about with spell books, paper, and ink. Sorcerers have magic as an inate ability and their discover their power as they use their natural gift. But warlocks are NOT learners or have natural talent for magic, they receive their magic from their patrons...and so it can be revoked.
